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The runtime environment for ONC/RPC programs, both client and server side.
/*
* $Header: /home/harald/repos/remotetea.sf.net/remotetea/src/org/acplt/oncrpc/OncRpcClientStub.java,v 1.1 2003/08/13 12:03:44 haraldalbrecht Exp $
*
* Copyright (c) 1999, 2000
* Lehrstuhl fuer Prozessleittechnik (PLT), RWTH Aachen
* D-52064 Aachen, Germany.
* All rights reserved.
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Library General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this program (see the file LICENSE.txt for more
* details); if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*/
package org.acplt.oncrpc;
import java.io.IOException;
import java.net.InetAddress;
/**
* The abstract OncRpcClientStub class is the base class to
* build ONC/RPC-program specific clients upon. This class is typically
* only used by jrpcgen generated clients, which provide a particular
* set of remote procedures as defined in a x-file.
*
* When you do not need the client proxy object any longer, you should
* return the resources it occupies to the system. Use the {@link #close}
* method for this.
*
*
* client.close();
* client = null; // Hint to the garbage (wo)man
*
*
* @see OncRpcTcpClient
* @see OncRpcUdpClient
*
* @version $Revision: 1.1 $ $Date: 2003/08/13 12:03:44 $ $State: Exp $ $Locker: $
* @author Harald Albrecht
*/
public abstract class OncRpcClientStub {
/**
* Construct a new OncRpcClientStub for communication with
* a remote ONC/RPC server.
*
* @param host Host address where the desired ONC/RPC server resides.
* @param program Program number of the desired ONC/RPC server.
* @param version Version number of the desired ONC/RPC server.
* @param port port number at which the ONC/RPC server is listening
* for interested clients.
* @param protocol {@link OncRpcProtocols Protocol} to be used for
* ONC/RPC calls. This information is necessary, so port lookups through
* the portmapper can be done.
*
* @throws OncRpcException if an ONC/RPC error occurs.
* @throws IOException if an I/O error occurs.
*/
public OncRpcClientStub(InetAddress host, int program, int version,
int port, int protocol)
throws OncRpcException, IOException {
client = OncRpcClient.newOncRpcClient(host,
program, version, port,
protocol);
}
/**
* Construct a new OncRpcClientStub which uses the given
* client proxy object for communication with a remote ONC/RPC server.
*
* @param client ONC/RPC client proxy object implementing a particular
* IP protocol.
*
* @throws OncRpcException if an ONC/RPC error occurs.
* @throws IOException if an I/O error occurs.
*/
public OncRpcClientStub(OncRpcClient client)
throws OncRpcException, IOException {
this.client = client;
}
/**
* Close the connection to an ONC/RPC server and free all network-related
* resources. Well -- at least hope, that the Java VM will sometimes free
* some resources. Sigh.
*
* @throws OncRpcException if an ONC/RPC error occurs.
*/
public void close()
throws OncRpcException {
if ( client != null ) {
try {
client.close();
} finally {
client = null;
}
}
}
/**
* Calls the "null procedure", which should always be provided
* by a remote ONC/RPC server.
*
* @throws OncRpcException if an ONC/RPC error occurs or
* the client stub does not have
* a client proxy to use for the call.
*
*/
public void nullproc() throws OncRpcException {
/*
* Do we have a client proxy?
*/
if ( this.client == null )
{
/*
* No.
* As the client stub does not know anything of
* the desired ONC/RPC server, there is no chance
* to (re)establish a connection to it. Therefore
* a generic RPC - failure exception is the only choice.
*/
throw new OncRpcException(OncRpcException.RPC_FAILED, "ONC/RPC client is not connected.");
}
else
{
/*
* Yes, then let's try the call.
*/
this.client.call(0, XdrVoid.XDR_VOID, XdrVoid.XDR_VOID);
}
}
/**
* Returns ONC/RPC client proxy object used for communication with a
* remote ONC/RPC server.
*
* @return ONC/RPC client proxy.
*/
public OncRpcClient getClient() {
return client;
}
/**
* Sets a new ONC/RPC client proxy, which will be used for future
* communication with a remote ONC/RPC server.
*
* @param client Passing null has the same effect as calling
* method {@link #close()} on this object. Passing the same client
* proxy will not have any effect.
* Otherwise the actual client proxy will be closed and the
* passed client proxy will be set.
*/
public void setClient(OncRpcClient client) {
/*
* Differs the passed client proxy from the
* actual client proxy?
*/
if ( this.client != client )
{
/*
* Yes, they differ. Then we should close
* the actual client proxy first, before
* setting the new client proxy.
*
* A probably raised exception will be ignored.
* In any case the passed client will be set as
* the new client proxy.
*/
try
{
this.close();
}
catch( OncRpcException ignoredRpcException )
{}
this.client = client;
}
}
/**
* The real ONC/RPC client which is responsible for handling a particular
* IP protocol.
*/
protected OncRpcClient client;
}
// End of OncRpcClientStub.java